PB2065: IMPORTANCE OF PET AS A PROGNOSTIC MARKER IN TREATMENT STRATEGY CHOICE IN PATIENTS WITH HODGKIN LYMPHOMA
Authors: O. Novosad, I. Pastushenko, T. Kadnikova, I. Tytorenko, A. Martynchyk, O. Gorbach, A. Ashyhmin, Y. Kmetyuk, O. Karpova, L. Mykhalska, O. Kindrakevych, M. Novikov, O. Oliinichenko, I. Kriachok
Journal: HemaSphere (2022)

Background: The systematic use of PET in staging is based on international guidelines. The accuracy of PET/CT over CT scanning (with a sensitivity and specificity higher than 90%) has been compared in several works in order to assess the extent of the disease, leading to modifying the staging in 15%-40% of cases with an impact on the therapeutic strategy in approximately 15%-20% of cases. Aims: The primary endpoints were to assess a correlation between PET findings and response to therapy, type of regimen and clinical outcome (relapse/death), as well as whether there is a difference when patient treatment is intensified or not intensified depending on PET findings. Methods: This substudy was performed within the framework of a wider prospective multicenter study on the predictive value of PET response assessment (249 patients with HL up to 65 years of age or younger). Patients received a treatment with ABVD or ABVD/AVD; BEACOPP-14/esc or “switched-regimens” (ABVD+BEACOPP-esc/14, BEACOPP-esc/14+ABVD). Metabolic PET imaging was performed to routine protocols using Deauville criteria for response assessment. Interim PET (PET2) was performed at 15.5 ±3 days (range, 5-26) after the 2-3 cycle of treatment. Results: 9 patients of the trial group had the 1st stage, 127 people were stage 2, 47 and 66 had stage 3 and 4, respectively. Most patients had stage 2A recorded, 35% of patients (86/249). 75.9% (189/249) and 24% (60/249) had the IPS factors of risk£2 and 33, respectevly (p>0.05). 63% (157/249) of patients went through an ABVD regimen treatment; only 9 patients of this group were switched to an ABVD/ABV course of treatment after receiving CMR, in accordance to PET. The ORR was 85% (212/249): where 91% of patients (195) achieved CMR and 9% were with PMR. In total, the disease progression occurred in 18% (45/249). In patients with PMR (4-DS) after 2 courses of treatment, the relapse frequency was significantly higher (47%) compared to the CMR (8%), р>0.05. 5-year event free survival (EFS) rate and overall survival (OS) for study group were 70% and 88%, respectively. We confirmed a significant difference between the 5-year EFS rate for patients with PET2+ vs PET2-. Thus, PET2- patients with early and advanced stages had an EFS level much higher than the PET2+ patient group (80% vs 30% respectively, Log-rank test, p<0.0001). However, when comparing the EFS level in patients with 4-DS vs 5-DS, we did not find any statistically relevant difference (р=0.2). EFS level in patients with PET-negative (PET3-) end of treatment was also much better compared to patients with PET-positive (PET3+) one, (83% vs 20%, respectively Log-rank test, p<0.0001). The 5-year OS findings in patients with PET2- and PET3- are significantly better compared to PET2+ and PET3+ (98% vs 35% and 97% vs 50%, р=0.04). Summary/Conclusion: Our findings have confirmed one more time that a good response to therapy achieved early enough leads to an increase of general relapse-free survival. This way, the issue of customizing treatment currently remains quite an important questions.